Mechanism reversible without backlash error



ay 3y 192?.

Y Y 1,627,236 R. M. GALLOWAY MECHANISM REVERSIBLE wgwnouw BACKLASH ERROR Filed March 24, 1925 9 Sheets-Sheet 1 LIUU May 3,1927. 1,627,236

- R. M.\GALLOWAY rwcrmmsu REVERSIBLE wi'rnouw BACKLASH ERRQR Filed March 24. 11925 9 Sheets-Sheet 2 @JYMWW May 3,1927.

R. M. GALLOWAY MECHANISM REVERSIBLE WITHOUT BACKLASH ERROR Filed March 24, 1925 9 Sheets-Sheet '4 Wvemioz I a WMMM%MW ,QZW

May '3, 1927.

1,627,236 R. M. GALLOWAY MECHANISM REVERSIBLE WITHOUT BACKLASH ERROR Filed March 24, 1925 9 Sheets-Sheet 5 v flaw/"01 Mam/ 9 Sheets-Sheet 6 R. M. GALLOWAY Filed Ma'fch 24. 1925 May 3 19270 MECHANISM REVERSIBLE WITHOUTUBACKLASH ERROR May 3, 1927. 1,627,236

R. M. GALLOWAY MECHANISM REVERSIBLE WITHOUT BACKLASH ERROR Filed Ma ch 24, 1925 9 Sheets-Sheet awue/wboz May 3, 1927*.

R, M.- GALLOWAY MECHANISM REVERSIBLE WITHOUT BACKLASH ERROR Filed March 24. 1925 9 Sheets-Sheet 8 May 3,1927. 4

. R. M. GALLOWAY MECHANISM REVERSIBLE WITHOUT BAGKLASH ERROR Filed March 24, 1925 9 sheets-Sheet 9 Ejvwzmtoz WM m 35% a oha/14 01 M Patented May 3 UNITED? STATES pPATE N l OFFICE.

, ROBERT gm. GAIJLOWAY; OF monmonninnmna, ASSIGN'OR 'ro TEE amona, AUTO,-

MATIC TOOL COMPANY, OF RICHMOND, INDIANA, A CORLPORATION OF INDIANA.

MECHANISM REVERSIBLE wrrnon'r ZBACKLASH ERRoR.

Application filedM arch 24-, 1925. Serial No. 17,969. I

This invention deals with mechanism in made for lost motion of any predetermined extent and in a manner providing for a-reversal in motion without shock, i. e., either positively in combination with a :gradual accelerating prime-mover or in combination with an abruptly acting reversing clutch in this instance, the shock absorbing resilient capacity, being an inherent characteristic of the lost motion device.

In various types of machines, i-t is important that a definite amount of motion will: be lost at a certain cycle in the opera: tion of the machine; especially where separate lines of transmission involving different degrees of back-lash must be synchro-.

nized immediately following a reversal in the direction of action of one orboth of'the separate transmission. This, for example, is exhibited. clearly in certain types of niachines for tapping or threading holes.

In such machines, the tool which cuts the motion resolved into two components, ,to wit, that of translation ordinarily termed the feed and that of rotation, ordinarily termed the speed. "In short, the compound motion is simply that of an advancing screw. Now, the-spindle has this motion and it carriesthetap but, in large machines used for other'work such as drilling, etc, the componcnt motio'ns of the spindle are varied or changed to meet different requirements by means of change gears appropriately placed in the separate transmission controlling the feed and the speed respectively. But, inasmuch as speed change gearing necessarily provides considerable back-lash and may not always correspond withabsolute precision to the particular ratio ofmovement required for 'a given tap, it is usual to resort toa safe guarding feature which provides a certain amount-of allowance,- so ,to speak, -inthe mounting of 'thetap on the spindle. In other words, the tap has a certain am'ount-of independent slide on the spindle but no relative rotation with regard to the spindle. This "longi:

tndinal play between thetap and the spin-- dle on which it is mounted is provided for by a conventional construction of: the tap holder itself.

.ing conditionsin the machine tool. For

convenience, these two forms will hereinafter he referred to as positive and impositiveJ? The positive tap holder} is:

usually used in constructions in which there 1S II10 I' back-lash in the'ffeed transmission than mthe ,sp eed. This type of tap -hold- ;e1- is so constructed thatnormally the taphol'dmg portion may m ov axially away from the shank-portiontoward the work but is held against movement in the opposite dlrection by a suitable retaining wall.

Therefore, as the. tool-spindle and thetap holder (and-tap ,carried.jthereby) are rotated andv fed -toward thework thetapis .fed positlvely into. engagement with-the work'and must cuta thread in itsfirst rotation after .contactingwith the work. When this type of tap-holder is used theyfeed of the tool vspindle is regulated to bejust threads (the tap) must, of course, have its slightly" slower than the self-feed of the tap dneto the pitch of its teeth and its rotations ,Therefore', during the tappingof a feed, be actuated toreverse both trans- 1 missions the transmissionhaving the least back-lash will be the first to becomeefi'eo" tive. As hereinbefore stated, there is more back-lash in the'feed than in the speed, and

therefore the tap will. start to ,rotate reversely before the spindle and the shank of the. tap-holder have beguntheir reverse feed. Inasmuch as reverse rotation of the tap will cause it to unscrew from the work,

which results in axial movement of the tap and its holding portion, most (if not all ment. Now it is to be remembered that the spindle feed is regulated to be slower than the self-feed of the tap; therefore, before thetap is completely unscrewed from its tapped hole, all .of the clearance will have been taken up and the relatively faster self feed of the tap will be attempting toeverrun the relatively slower feed of the tap holder.'. This however is precluded b the contact of the. tap-holding portion wit the retaining wallof the shank portion, with.

' the result that either the tap or the threads in the work must'break. a This invention rectifies the aforesaid de-' feet bys'suitably combining with the ele-} ments ofthe machine, as. above described,

a peeuliar lost-motion device which is coni trived to introduce (at the time of reversal) suflicient lag in the spindle-rotating trans "mission to enable the aggregate back-lash in the spindle translating transmission to betaken up and the reverse feed inauguaway from thework and is normal tap-holding portion and a cooperatingpart i of its play the self-feed of the tap will either keep pace rated before the reverse rotation starts. This construction permits the reverse feed to start in advance of the reverse rotation of .the ta whereby the relatively faster selffeed of t ta Wlll notovertake the slower' spindle feed store the tap has emerged from its tapped hole and therefore no damage will be doneeither to the tap orto the- I In the impositive tap-holder the float is in the direction opposite to that in the positive tap-holder; in other words the tap holding portion is permitted to move upwardly on the shank portion yheld against movement-on the shank in a direction toward. the work b contact between a suitable retaining wal provided by the provided by the shank portion. This type of tap-holder may be used to advantage in (tapping machines in which "the aggregate back-lash in the spindle rotating transmlssion is greater than the aggregate back-lash in the spindle feed transmlssion.

In, a machine fitted with an impositive tap-holder, when a hole is about to be tapped, the spindle carrying the. tap in its lowermost osition is being rotated and si-' multaneous y translated towards the work.

' quently the that the tap does not bite into the work until forced into it by spring pressure produced by the take-up of a part on the ;spindle, but thereafter,

with the feed of the spindle or perhaps slightly under-run it thereby slightly separating the retaining wall andthe-coop fi' ing portion of the shank.

his mechanism works satisfactorily as described so long as it'is' feeding in "but, unless the whole machine be very accurately timed, built and adjusted, a strippingo'f the 7 threads-or at least an injury thereto is likely to occur when the parts are reversed for the purpose of withdrawing the tap from the work. What happens is that there may more' accumulated back lash in the-trans mission which rotates the spindle; than .in

the] separate transmission which feeds it.

If so, fwhenthe reversaltakeS place, the feed transmission will take effect on the spindle before the other'transmission starts to rotate it reversely. I

The consequence is that the spindle and the shank of the tap-holder will start to re-A.

cede from thework before the tap starts its reverse rotation with the result that all, ;(or

substantially all) of the clearance between the retaining wall .and 'thecooperating part of the shank will be taken u before the tap starts to rotate reversely. nasmuchas the self feed of the tap is slower'than the positive,feed of theespindle it will readily be- I perceived that before the tap has emerged from the tapped hole the ositive feed will be acting to withdraw t e tap from the hole at a rate faster than the rate of reverse rotation of the ta will permit, with the re-I s'ult that-either t e tap .must .break'oi: the ,7

threads in the work must strip.

- This invention also is adapted to correct this inherent defect in tapping machines in which the excess back-lash is in the spindle rotating mechanismu This is accomplished reversal, thestarting of the feed transmisby g embody-ing a lost-motion device in the spindle feeding transmission whereby, upon sion is delayed sufficiently to enable the tap rotating transmission to become eflectiv'e first whereupon, through the self-feed of the tap in a reverse irection, additional clearance will be produced between the re--' taining wall of the tap-holding portion and time the reverse feed becomes effective there will have been produced more clearance than the differential between'the relatively faster spindle feed and. relatively slower.

self-feed of the tap may take u before the \tap is unscrewed from the tappe hole,,therefore there .willibe nmint'erferemre between the power feed andthe self-feed of the tap and the tap will be backed out without strain on either the tap or the work.

The type of lost motion connection shown in this application comprises a driving and a driven member with a variable number of the cooperating part of the shank. By the I floating plates inserted between them. The

amount of lost-motion is 'preferabl determined by varying the number of p ates included between the driving member and the driven member. Lugs, whichproj from the driving and the" driven members and from the floatingplate's, are arranged to move the same paths of movement 'so as to engage each other. The amount of lostmotion is not only" 'controlled'by the 'num 'ber of floating plates but by the thickness of the lugs on the plates an and driven members.

When a reversing motor is utilized for reversing a machine of the above indicated d on the driving I type, having a lost-motionconnection, it has been' found unnecessary to provide the connection with any yieldlng or. resil ent means ,to withstand shocks. 1 The reversing of the direction of rotation ofthe motor. compels it to start from zero speed andgradually increase to the full load speed. Accordingly no shock absorbing Y means "is necessary in the lost-motion connection. f However, in case the machine is reversed by mechanism in the form of a jaw-clutch or-a" similar inechanism,- it is very desirabletoprovide shock absorbing means inthe lost motion connection. Preferably resilient means "is pro- .vided for preventing the direct engagement of the taps by the internal stress and strains to which they are subjected. The pause in the movement of the taps-which is caused by the lost motion connection. permits the stresses and strains which have accumulated in the taps during the tapping operation to dissipate themselves before the reversal in the movement of the taps takes place.

Other objects and advantages will be in part indicated in the following description and in part rendered apparent therefrom in connection with the annexed drawings To enable others skilled in the art so fully to apprehend the underlying features hereof that they may embody the same in the various ways contemplated by-this invention, drawings depicting a preferred typical construction have been annexed as a part of this disclosure and, in such drawings, like characters of reference denote corresponding parts throughout all the views, of which Figure 1 is an elevational view of a tapping machine having a hand-control for the power feeding and provided with a lostmotion coupling constructed in accordance f withmy invention. Fig.2 is h fronteleva- 'tional'v'iew of an automatic tapping machine constructed in accordance'with my inv nj tion. 'Fig. 3 is. a side elevational of the machine .shownin Fig; 2. Fig. 4' is. a plan view of, the machine shown in'Fig. 2.

; Fig.5 is a sectional view along-the line 55' section along theline 6"6 of Fig. 5. f F g. is a sectional view along the line 77 of Fig. 5 Fig. 8 is a sectional viewalongthe line 8 8 of Fig. 2/ Fig. 9 at sectional of Fig. {1. Fig. 6 is aplan-view partly in view along the line 9-9 of Fig. 4'. {F 10 is a plan view of the differential trolling. mechanism. Fig. 11 is an elevational View partiall in "section of a lost motion connection a: apted to be usedin'my machine. Fig. 12 is a gear consectionali'view Ialong the line 12 12 of Fig. 13. 13v a sectional view along the line 13'13 of Fig. 12. Fig. 14 is an elevational View partially "in section of a lost motion connection having shock absorbing elements.

nectionshowni'n Fig.14. 3 Referring 'to Fig. 1 of theZdraWings a hand feed tapping machine is"illustrated provided with 'a lost motion'coupling. In,

e 15 is *a sec-; t tional view along the line 15 15 of th'e'conto relieve the tap of the stresis 'and strains ;1

" produced I during the tapping. v operation. The machine'shown 'in Fig. l, accordingly, fser'ves not only to lengthen the life of the taps but also takescare of theshockpro duced by the abruptly acting jaw-clutch therein. g

The tappingf'machine shown in Figi 1., comprises a base 185 fromwhichfprojects 'a column or frame 186. "Th'e'column 186 carries a work-table"l87,a*nd a. tool head h 188. The work-table 1 87'1is operated on .a suitable guideway by' means. v of Ya I hand crank 189. v The. head. I88, which 'mounted on suitable g'uide'waysi on the column 186 carriesa number of 190. -The taps, which are not illustrated in the drawing, are, carriedby thh 'l 90.-,The tool spindles"ltloj are i otated by means of a main spindle 19:1ivfhich is connected by suitable gearing "contained'in a casing 196 to a main drive. lost motion connection 192 having yieldingelement-s incorporated therein is connectedbetween"the main spindle 191 and the 'drill spindles 190. The tool head 188' is ra'ised and means of a power feed" shaft '192Fduring a drilling I by means 'of the hand-wheel'19'7 du'ring a tappingoperation.

lowered by operation and is raised and lowered tool spindles spindles A completedescriptionand, illfusti ation of 1.

necessary inasmuch as thetapping machine shown in Figs. 2 to inclusive is completely described and illustrated in, detaiL. The

lost motion coupling 192 is described when 23 1 with a hand-feed machine as shownj in Fig.

1 performs three functions for improving the operation of the machine. .At the end of the tapping movement and when the holes.

have been tapped, the reversing of the direc tion of rotation of the main spindle 191 does not immediatelyreverse the direction of rotation'of the taps by reason of the lost motion included in.the coupling 192. .The pause thus produced in the rotative movement of the taps permits the stress and strains produced in the taps during the tap- .ping to be dissi ated. Moreover the pause thus produced in the rotation of the tap warns the operator of the machine to rehead. Furthermore the coupling 192 coshions the -shock produced by reversing the direction of rotation of the main spindlev 192.

Referring to Figs. 2 to 10, inclusive of the drawings, an automatic tapping machine is illustrated which is constructed in accordance with my invention.- -The illustrated tapping machine comprises a base member 1 having an upstanding-column 2 mounted thereon. on suitable guideways 4'and 5. A plurality of taps 6, only one'of which is illustrated on I the drawings-is carried by the tool head 3.

A suitable work table for supporting the work may be provided below'the tool head 3.

Inasmuch as my invention is not particularly concerned with the table carrying the work, description of such table is omitted from the specification.

A main driving spindle 7 i is provided foroperating the taps 6 and a lost motion connection 8 is pro ided between the main driving spindle 7 and the tool head 3. A complete descriptionof the construction'and operation of the lost motion connection 8 will be given hereinafter. The main driving spindle 7 is connected to a motor 10 by means of a speed shaft ,11 shown in Figs. 2 and 30f the drawings. I Themotor 10 not only serves to operate the main fdriving spindle 7 but also operates a feed shaft 12 forefi'ecting vertical movement of the-tool head 3 on thecolumn 2.

' 5 The speed shaft 11.has a spline connection with a gear wheel 15 which is supported on" a bracket 16. The bracket 16 is sup orted. on the head 3 which carries the main riving spindle 7. Referring to Fig. 9 of the drawings, the gear wheel 15 is shown connected through gear wheels 17, 18 and 19 to a verse the direction of movement of the tool connected to. the main driving motor 10, A bevel gear wheel 35, which is mounted The column 2 carries a tool head 3 s indle 7. e spline connection between to speed shaft 11 and the gear wheel-15 ear w eel permits the free vertical movement of the tool head'3 and the'bracket 16 which is carried 1 upon A" weight-member -(not shown) is provided forcounter-balancing the weight of the tool head 3 and thus assist. the feed mechanism in o rating the tool head along the column. he weight member connected to the tool head 3 by means- .of cable 26 which extends over pulleys 27 at the top of the column '2.

A bevel gear wheel. 29 is connected to the lower end of the speed shaft 11 as shown in-Fig. 3 of the drawings. Such bevel gear wheel 29 meshes with a second bevel gear wheel 30 which is mounted on a shaft 31.

The shaft 31 carries another bevel gear wheel 32 which meshes with a bevel gear wheel 33 on a shaft .34. The shaft 34 connects with a main control mechanism which in turn is on the shaft 34, meshes with a bevel gear wheel 36 which is carried by ashaft 37 in the.transmission'mechanism. The shaft.

37 projects through a'transmission box 38 and carries a gear wheel 39 near the end thereof. The

apinion 40 which is mounted on the armature shaft of the motor 10. i

In, the above described; construction it will be noted the speed'me'chanism, which I I rotates the main spindle 7, is directly connected to the motor 10 without the interposition of clutches. The connection between the motor 10 and the main drivin spindle 7 comprises the shaft 37, the sha t' ear wheel-1i39 meshes with umn 2,,carries a worm member 41 near the I upper end thereof. Theworm member 41; meshes with a worm wheel 42 which -is mounted on a shaft 43. The shaft 43 is provided with hearings. in .a bracket 44 which is carried; by the column 2. The

shaft 43 carriesla pinion 48 which meshes with the gear wheel 49 on a shaft 50. The

.- shaft 50 1s mounted to have sliding movement in the column 2 in order to disconnect the power feed whenever it is desirable to effect feeding movement of the head by shaft 50, meshes with a gear-wheel 25 The gear-wheel 25 meshes with a rack 52 0n the column 2,-as shown in Fig. 8 of the drawings. A hand wheel 53is' provided on the end of the shaft 50, as best shown in Figs. 2 and 8 of the drawings, and a spring mem- 'hand. A. pinion 51,'which is formed on the I i with the pinion 48. If it is desired to effect hand-feeding of the head,the shaft is moved towards the left, asviewed in Fig. 8 of the drawings, to disconnect the gear wheel 49 from the pinion 48. l

The lowerend of the feed shaft 12 carries a bevel gear wheel 28 which meshes with a in Fig. 2 of the drawings. The shaft 58 carries a second bevel gear wheel 59 which meshes with a. bevel gear 60 on the shaft 61. The shaft 61 connects with the main motor 10 by means of the main transmission mechanism above referred to. A shaft 63 in the transmission mechanism carries a bevel gear wheel 64 which meshes with a bevel gear wheel 65 on the shaft 61.

nism 66 intermediate the ends thereof, as shown in Fig. 5 of the drawings. The differential gear mechanism comprises two end bevel gears 67 and. 68 which respectively ,central portion 73 of the difl'erential gear mechanism. The central portion of the differential gear mechanism is keyed to the shaft 63*. The differential gear mechanism 66, as above described, is old and well known and varies the speed of rotation of the shaft 63 in accordance with relative speed of the two spur gear, wheels 69 and 70. If the spur gear wheel 70 is held stationary and the spur gear wheel 69 is rotated at a pre determined speed, then the shaft'63 is ro tated' in the same direction and at half the speed of rotation of the gear wheel 69. If the gear wheel 70 is rotated in a reverse directionand at a different speed as compared with the gear wheel 69, then the shaft.

63 is rotated at one half the difference in rotation of the gear wheels 69 and 70. The spur gear wheel 69 is rotated at a faster rate than the spur gear wheel 70 and thus no change in the direction of rotation of i the shaft 63 is effected by the differential gear mechanism. \Vhen the, gear wheel 70 is held stationary, the shaft 63 is-rotated at a relatively rapid rate to effect traversing movements by the head.-- .When the gear wheel 70 is rotated simultaneously with the gear wheel 69, the shaft 63 is rotated at a much slower rate to effect feeding movement by lthe head. The direction of rotation of The shaft 63 carries a differential gear media-- the shaft. 63 and accordingly the direction the head is controlled by the able bearings in the transmission box 38..

The spur gear wheel 70. is connected to a gear wheel 77 by means ofan idlergear 78; The idler gear? 8 is mounted on a shaft 79 carried by the box 38. The gear wheel 77 is keyed to a bushing 80 which is rotatably mounted on the shaft 7 6, as shown in Figs;

4 and 5 of the drawings; The bushing 80 also carries one member 81 of a clutch mecha bevel gear wheel 57 on a shaft 58, as shown anism 82. The clutch member 81 issplined to the bushing 80 and is provided with clutch member 84. .A pin 87, which is secured to the lower end of the lever 85, projects into a groove 88 formed in the member 81.. A second lever 89, which is fixedlymounted on the shaft 86, carries a pin 90 which projects into the groove 88. The upper end of the lever 85 carries a pin 91 which engages a collar 92 sl-idably mounted on a shaft 93. All-shaped member 94 is slidably mounted on the shaft 98 'by means of a set screw 95 and spring members% and 97 are mounted on the shaft between theends of the U-shaped member 94 and the collar member 92. The member 94 is operated by means of a lever 98which ex-.

tends to the front of the box 38 and is pivotally connected to a bell-crank lever 99. The

lever is secured to the -U-shaped member 94 by means of the bolt 95. The bell-crank lever 99 is pivotally supported at 100 and in turn is connected to a link 101. The link 101 is connected to a lever 102 which is operated by a hand-lever 160 as shown infFigs, 3', 4 and 10, tocontrol the operation of the clutch mechanism 82. V

The lever 98 which controls the clutch mechanism 82 is also operated automatically in accordance with the movement of the tool head. A rod 161 as shown in Figs. 3 and 10 of the drawings is. so supported on the column 2 as to have a limited movement in accordance with the, movement of the head.

A lug 162-on the, head 3 is adapted to engage a yielding pin 163 on the rod 161 to effect movement of the rod. When the rod 161 is moved: to the limit of its movement the pm the pin 163 is againengaged to move-the rod 161 in areverse direction. The rod 161 has mesh with a pinion 165 on a shaft 166; The

rack teeth formed on itslower end which shaft 166 carries a second gear wheel 167 which engages a rack 170 on the lever. In

.such manner the clutch 82 is controlled in accordance with the movement of the head. The head is moved downwardly at a rapid rate until the ta s are about to engage the work. At such timethe lug 162 operates the rod 161to engage the clutch 82 and efiect a slow-feeding movement. At the end of the tapping ope'ration'the motor is reversed from the controller 110 by means of the lug 112 engaging the lever 111. When the ta clears the work the lug 162 operates the ro 161 to disengage the clutch 82 and effect a rapid traverse movement upwardly of the head.

The clutch member 81 isprovided with two rejecting lugs 105'and 106 oneof which is a a ted to e'ngage a stop member 107 when t e clutch mechanism 82.is'in the disengaged position. The stop member 107 is secured to the box 38 as shown in Fig. 6 of.

the drawingsand serves to prevent rotation of the clutch member '81 and the gear wheels 77 and 70 when the clutch mechanism 82 is disengaged and a rapid traverse operation is being eflected. When the clutch mechanism .82 is engaged, the projecting lugs 105 and 106 are moved so as not to engage the stop member-107. Accordingly, it is apparent in one position of. the clutch mechanism the gear wheel 70 is held stationary to rotate the shaft 63 at half the speed of the gear wheel 69 and in the opposite position-0t the clutch mechanism 82the gear wheel 70 is rotated in a directionopposite to' the direction of rotation of the shaft 69 and at a slightly difi'erent rate to effect rotation ofthe shaft 63 at I half the difference in speed of rotation of the gear wheels 69 and 70.

In the above described mechanism it will be noted a shifting movement of the lever 98 serves to effect a movement of translation of the U-shaped member 94. One end of the springs 96 and 97 engages the collar member 92 for operating the lever 85 which controls the clutch member 81. The spring members 96 and 97 serve to effect "a yieldin 'g 'engag ement between the clutch teeth on'the clutchmembers 81 and 84.

The shaft 76 carries a gear "wheel 103 which meshes with a gear wheel 104'on the shaft 37. The gear'wheel 103 'is keyed to the shaft 76 and serves to maintain the shaft 76 in rotation whenever the motor 10 is-in rotation. Thus, it. is apparent when the clutch 82- is disengaged, the shaft 63 is.

operated at a predetermined speed which is half the speed of rotation of the gearwheel 69. However, upon engaging the clutch the gear wheel is operated at a slightly different speed .as compared with the gear wheel 69 andin a reverse direction. In such T a case, the shaft 63 is operated at half the difference in speed of rotation of the gear wheels 69 and 70. The slow speed of the shaft 63 is used during the power feeding of the head 3. The fast speed of shaft 63 is used during the traversing movement of the head either towards oraWay'from the work depending 'on direction'of rotation of the motor.

of'themain spindle 7 andthe movement of the head 3 in'the above indicated manner, ,is governed by acontrol box 110. A'control The motor 10, which controls the rotation ated to raise the head from the workiand 4 h at the same time to'reverse the direction of the rotation of the main driving spindle, in

order to permit the withdrawing of the taps I from the work.

It will be noted in the above described machine, a single source of power is provided for operating two separate branches of a transmission mechanism; One branch,

as above described, effects rotation of thetaps on the machine and the other branch serves to feed the head which carries the taps. Inasmuch as the two branches of the transmission mechanism are interconnected no trouble isrencountered during the tapping operation to maintain the linear movement and the rotary movement of the taps in correct relation. However, upon completion of the tapping operation, it is necessary to reverse not only the direction of rotation of the taps but also to reverse the linear move-- ment of the taps. Each of said branches in the transmission system have more or less back-lash and it isnecessary to take care of such back-lash if the taps are to be withdrawn from the work without injuring the threads which have been cut. It is not only necessary to have the linear movement and the rotative movement effected in a predetermined ratio during the withdrawing movementbut it is also necessary to insure that the'self-feed of the tap and the movement of the tap-holder efiectediby the feed mechanism will not conflict. The branch of the transmission mechanism which operates-the power feeding of the-head, generallycontains more back-lash than the branchof the transmission system which efiects rotation of the taps. *Accordingly,'a predetermined amount of lost motion or backlash is inserted in the branch of the trans-"- mission system which efl'ects rotation qt the taps. Thus, it is apparent in a. machine constructed in accordance with my invention,

. floating plate 148. The floating plate 148 is adapted to be operated by the driving member 151. A lug 152, which pro ects 'from the sleeve member 144, is positioned ing plate.

of the drawings, are positioned on opposite sides of the projecting lug 154onthe float- Spring members similar to. the spring members 156 and 157 are positioned on opposite sides of the lug 153 which project from the floatin plate. The floating ring 150 serves to hol the two s ring members 156 and 157 in'position'to e engaged by the lugs 154 and 155 and the floating ring 149 serves to hold the two spring members associated with the lugs 152 and 153 in position to be engaged by such lugs. A casing or housing 156 is provided for enclosing the, coupling and is preferably secured to the sleeve member 144- by means of a set.

screw 158. I

Assuming the driving spindle 7 to be .rotating in a clockwise direction, the lug 155 (ill.

projecting from the driving member 151 compresses .the spring 156 between it and the lug 154 projecting from the floating 155 and the length of the spring member plate 148. The lug 153 projecting from the opposite side of the plate 148 compresses the .spring between .it and the lug 152 which projects from the sleeve-member 144. The spring members serve to.cushion the connection against an abrupt shock such as is produced by a quick-acting reverse mechanism. Upon reversing the directiorrof a rotation of the spindle 7 the lug 155 is moved to the dotted line position shown adjacent to the spring member 157 in Fig. 15 ofthe drawings. The counter-clockwise rotation of the driving spindle compresses the spring 'ecting from the plate 148. It will be noted, owever, that before the lug 155 engages the spring member 157, the' spindle 7 and the driving member-151 have made one revolution-less the thickness of the lugs 154 and 1,57. The compressingof the spring 157 serves to cushion the shock produced by an abrupt reversing mechanism. The plate 148 is rotated through one revolution less the thickness of the lugs 152 and 153 and the length of one of the spring members before effecting any movement of the driven mernher 144. A fined and rigid connection between the spindle 7 and the driven shaft 144 is not effected until after complete compression of the springs which are located be- I tween the lugs on the driving and'driven members and on the floating plate. v

Without further analysis, the foregoing member 157 between it and the lug 144 prowill so fully reveal the ist of this invention that others can, .by applying current knowledge, readily adapt it for various utillza- \tions .by retaining one or more of the features' that, from the standpointof the prior art, fairly constitute essential characteristics f for translatirigsaid spindle; a reversingmeans for said transmission; and a lostmotion coupling controllin the spindlerotating branch, said 'lpst-motion coupling providing alag so related to the aggregate back-lash of the transmission between the eo-- l reverser fandthe spindle as to defer the reverse turningof said spindle until it has begun its reverse translation.

2. A machine-tool combining a member.

pling controlling one of said branch-line transmissions, said lost-motion coupling being constructed to provide a lag not less than the excess of -the aggregate back-lash of'the other branch-line transmission over the,

aggregate back-lash of the branch-line transmission embodying said coupling.

3. A tapping machine combining a spindle has adapted to be simultaneously translated and' I rotated; a motion-reverser; two transmission means operated thereby, the one for translating and the other for rotating said spindle; and a lost-motion coupling in the rotation-imparting 'tIHIlSIIllSSlOIl means adapted to delay said means from reversely operating said spindle until said other means has started reversely to translate said spindle-f v 4. In a machine-tool, the combination comprising a cutting tool; a work member to be operated on by said cutting tool; feed mechanism for effecting relative linear movement between the work ,member and the tool; speed mechanismfor efi'eoting rela-.

tive rotation between the cutting tool and the work member, said speed mechanism being operated in timed relation to said feed mechanism and a back-lash compensating iao.

mechanismfor insuring the starting of the a lost motion connection embodied in the one of said mechanism-s normally having the least back-lash, to permit the other of said mechanisms to be 'rendered effective first upon reversal of the feed and speed mechamsms.

6. In a, machinmtool, the combination comprising a cutting tool: a work member connected to said cutting! tool by a thread: speed mechanism for ettecting relative rotation between the work lnember and the cutting tool; feed mechanism for ett'ecting mentbcin; eflected in'accordancc with the thread connection between the work member and. the cutting tool: and mechanism compensating for backlash to maintain the work member and the cutting tool in correct relation to each other upon reversal of the feed mechanism and the speed mechanism.

7. Ina -machine-t'ool, the combination comprising: a cutting tool; a work member adapted to be operated on by said cutting tool: teed mechanism for effecting relative linear movement between the work member and the cutting tool: speed mechanism for effecting: a relative rotativ'e movement between the cutting tool and the work mem- -ber. said feed mechanism and the speed mechanism being interconnected to maintain a predetermined ratio between the linear movement and the rotative movement; and back-lash compensating"mechanism for insuring the s tzirting ot" the linear movement and the starting ofthe rotative movement in correct relation upon'reversal ot the feed mechanism and the speed mechanism.

8. In a machine-tool, in combination. a tool; mechanism to rotate said tool; mechanism to feed said tool bodily during its rotation; a single reversing means for simul' taneously reversing" the tool feedingand rotating mechanisms;and a. delayed action device embodied in one of said mechanisms to produce a dwell therein to cause the othcr of said mechanisms to become ett'ective first; after the actuation of said reversing means.

9. In a machine-tool, the combination comprising a spindle; speed mechanism for rotating said spindle; feed mechanism operated in accordance with the o i eration of the speed mechanism for feeding said spindle; and a back-lash compensating mechanism between the speed mechanism andthe spindle for preventing rotation of the spindle until after the back-lash in the mechanism is taken up.

10. In a machine-tool, the combination comprising a plurality of spindles mechanism for rotating said spindles; feed feed mechanism operated in accordance with the operation of the speed mechanism for feeding said spindles, means for revers ng the direction of rotation of the speed mecha-i nism. and of the feed mechanism; and mechanism between the speed mechanism and the spindles for preventing the rotation of the spindles in areverse direction until the back-lash in the feed mechanism is taken up.

11. In a machine-tool, the combination con'iprising a tap; speed mechanism for rotating said tap in a forward and in a reverse direction; feed mcchanisnrfor moving the tap l'ongitudimilly in accordance with the operation of the speed mechanism; and

relative linear movement between the cuttin; Qmcchanism for preventing rotation of the tool and the work member, sald linear 1novcanism for rotating said tool in a forward and in a reverse direction; feed mechanism for movin; the tool longitudinally in accordance with the operation of the teed. mechanism and in a direction in accordance with the direction of the tool rotation; and mechanism for compensating for the back-lash in the feed mechanism upon reversal of the speed mechanism.

13. In a macliindtool. the combination comprising a tool head movable on the ma chine frame and having a number of taps rotatablv mounted thereon; a main spindle forrotating said taps; a speed'mechanism :tor operatin; said spindle; a feed mechanism for operating said tool head in accordance with the operation ot' said speed mechanism: and aback-lash compensating mechanism conncctcthto said spindle for insuring the taking up of the back-lash in the feed nurchanism prior to the rotation of the taps mourned on said tool head.

, ,l-t. lira nnuihine-tool. the combination comprising a tap: speed mechanism for effecting rotation of said tap in a t rward and in a reverse direction; feed mechanism for ctl'ecting linear movement of the tap in accordance with the rotativc movement there- 'of, the direction of linear movement being varied in accordance with changes in the direction of rotation of the tap: and a' lostmotion coupling between the speed mechanism andthe tap for preventing rotation of the tap in a reverse direction until the back-lash in the feed mechanism has been takennp. a

- 15. Ina machine-tool, the combination comprising a tap; a work member adapted to have a thread formed therein'by said tap; s eed mechanism for effecting rotation o said tap in a forward and in a reverse direction; feed mechanism for effecting linearmovement of the tap in accordance with the rotative movement thereof, the direction of linear movement being varied inaccordance with changes in the direction of rotation of the tap; and a lost-motion coupling between the speed. mechanism and the tap to insure the starting of the linear movement and the rota-tive movement of the tap in correct relation upon withth'awal of the tap from the work.

16. In a machine-tool, the combination comprising a tap; a work member adapted to have a thread formed therein by said tap; speed mechanism for effecting rotation of said tap in a forward and in a reverse direction; feed mechanism for effecting linear movement of the tap in accordance with retati've movement thereof; and a lost-motion coupling in one of said mechanisms'to insure the starting of the feed mechanism and the speed mechanism in correct relation upon withdrawal of the tap from the work.

17. In a machine-tool, the combination comprising a tap; a work member adapted to have a thread formed therein by said tap; tap operating mechanism for effecting a feeding and a rotativc movement of said tap to form a thread in said work member, said mechanism being operable in a reverse direction to withdraw the tap from the work; and a back-lash compensating mechanism for insuring the starting of the rotative movement and the linear movement of the tap in corrected relation uponlreversal of said tap operating mechanism.

18. In a machine-tool, the combination comprising a tap; a work member adapted to have a thread formed therein by said tap; tap operating mechanism for effecting a feeding and a rotative movement of said tap to form a thread in said work member, said mechanism being operable in a reverse direction to withdraw the tap from the work and a lost-motion coupling inserted in said mechanism for preventing rotation of the tap in a reverse direction until linear movement in a reverse direction is effected.

'19. In a machine-tool, the combination comprising a tool head movable along the frame of the machine; a tap carried by said tool head; a spindle for rotating said tap; speed mechanism comprising a system of gears for rotating said spindle in a forward and in a reverse direction; feed mechanism meanest:

comprising a system of gearing connected to said speed mechanism for moving said tool head along the machine frame according to the operation of said speed mechanism; and a lost-motion coupling for so connecting the speed mechanism to the tap spindle as to prevent rotation of the tap in a reverse direction until the back-lash in the feed mechanism has been taken up.

20. In a machine-tool, the combinationcomprising a .tool head movable along the frame of the machine; a tap carried by said tool head; a two-part spindle of which one part is connected to rotate said tap; speed mechanism comprising a system of gearing connected with the other .part of said spindle for rotating said spindle in a forward and in a reverse direction; feed mechanism comprising a system of gearing connected to said speed mechanism. said feed mechanism serving to move the tool head along the frame in a direction corrcspi'inding to the direction of rotation of the tap spindle; and a lost motion connection between the two parts of said spindle for preventing rotation of the tap in a reverse direction until the back-lash in the feed mechanism has been taken up.

91. In a machine-tool, the combination comprising a. tool head movable along the frame of the machine; a plurality of taps carried by said tool head; a spindle for ro tating said taps; speed mechanism connected to a source of power and con'iprising gearing for rotating the spindle in a forward and in a reverse direction: feed mechanism comprising gearing connected to said speed mechanism, and operated in timed relation thereto, for raising and lowering the tool head; and a lost motion connection between said spindle and the taps. said connection serving to prevent reverse rotation of the taps until the back-lash in the feed mechanism is taken up.

22. In a machine-tool, the combination comprising a. tap; a tool head carrying said tap and movable along the frame of the machine: a spindle adapted to effect rotation of said tap; a work member adapted to have a thread formed therein by said tap; speed mechanism for effecting rotation of said spindle; feed mechanism for effecting iinear movement. of said tool head and connected to said speed mechanism in order to maintain the ratio between the rotative movement and the linear movement to correspond to the thread on said tap; and back-lash compensating mechanism for preventing rotation of the tap in a reverse direction for withdrawal from the work until after the back-lash in the feed mechanism is taken up.

23. A machine tool combining a rotatable cutting tool a spindle for rotating said cutting tool; mechanism for rotating said spindle in forwardand in reverse directions; means active independently of the retation of the spindle to feed the spindle axially; and a lost motion coupling embodied in said spindle rotating mechanism for producing a pause of predetermined duration in the 'rotative movement only of the and a positively acting lost-motion coupling inserted between said" drive shaft and said spindles for producing a predetermined lag in the reversing of the rotation of the spindles upon reversing the rotation of said drive shaft.

25,1n a machinetool, the combination comprising a Work support: a rotatable member; mechanism for rotating said moms berina forward and in a'reverse direction; mechanism for effecting relat ve feeding movements 1n. reverse direction between the rotatable member and the work on said work-support; and a lost-motion coupling the action of that mechanism \vhen'the two mechanisms are reversed, said coupling having: resilient means for cushioning, the shock produced by the reversal of" said mechanism.

26. In a tapping machine. the combination eomprisime a prime mover; a rotatable and translatable tool-spindle adapted to carry a tap; a forward and a reverse spindle rotating drive between said prime mover and said tool-spindle; a forward and a rcverse feed for said tool spindle independent .of its rotating means; and a' lost-motion device embodied in'said rotating means inter- "inedia te the prime mover and the tool spindle to produce a prcdetermined' delay in the.

rotation ot the spindle when the reverse drive isrendered. effective.

27. Ina tapping machine, thecombination comprising aprime moyer; a rotatable and translatable tool-spindle adapted to carry a tap; a forward and a reverse spindle rotating drive between said prime mover and said tool-spindle; a forward and a reverse feed for said tool spindle independent of its rotating means; and a lost-motion coupling embodied in said drive intermediate the prime mover and the tool spindle to delay the rotation of the spindle when the reverse drive is IGIIClBIQd'Gfi GCtIVE, said coupling having resilient members for cushioning the shock produced upon the inauguration of the reverse drive.

28. In a multiple tapping machine, the eoml'iinationcomprising a plurality of taps;

a two-part main spindle; mechanism for rotatin; said main spindle; means for operatingsaid mechanism in forward and reverse directions; a tool-spindle intermediate the main spindle and each of said taps; and a lost motion connection betweenthe parts of the main spindle to produce a predeter dlesfwlien the main spindle, rotating mechanism is reversed.

mined delay in the rotation of the tool-spinembodied in one of said mechanisms to delay- 2-9. In a tapping machine; the combine tion co'inprisingatap; a main spindle for rotating said tap; mechanism for rotating said spindle; means for operating said mechanism in a torward and in a 'everse direcanism.

In witness xvhereofil have hereunto subscribed my name.

ROBERT M. GALIioW'AY;

tion; and a lost motion coupling for connectmg said spindle to the tap, said coupling 

